In the past few decades, government limits on the use of leaded fuels have led to the use of smaller gasoline fuel nozzles, designed to fit through “restrictors” in the fill tubes of gasoline-powered vehicles. These restrictors were designed to prevent the introduction of leaded gas into vehicles containing catalytic converters, which would be “poisoned” by the tetraethyl lead contained in older gasoline formulations. Another recent trend has been increasing use of diesel engines to power automobiles and other smaller vehicles, using low-sulfur diesel fuels. As a result, vehicles which an operator might have assumed to require gasoline in the past may now require diesel fuel instead, with correspondingly increased chances of incorrect fueling occurring.
Non-leaded gasoline fill nozzles are approximately 13/16 inch in outer diameter, with gasoline-powered vehicles being configured with restrictors in their gasoline fill tubes having openings corresponding to this size nozzle. Small vehicle diesel fill nozzles are slightly larger, approximately 15/16 inch in diameter, corresponding to the size of the older leaded gas fill nozzles. The restrictors in diesel-powered vehicles must then have openings correspondingly larger to accommodate this slightly larger size fill nozzle.
As a result, the restrictors in gasoline-powered vehicles have openings too small to allow insertion of low-sulfur #2 diesel fuel nozzles (as these nozzles have the same size as the old leaded fuel nozzles, the insertion of which the restrictor was designed to prevent). This situation generally minimizes the chance of accidentally introducing diesel fuel into a gasoline-powered vehicle. Unfortunately, the opposite error of accidentally introducing gasoline into a diesel-powered vehicle is not prevented by the restrictor mechanism, as the smaller gasoline fill nozzle fits easily through the larger opening in the diesel fill tube restrictor. In the past, when diesel power was generally employed only for larger trucks and very few smaller vehicles, this fueling error was less common. With the advent of modern diesel-powered smaller vehicles, such as those employing common-rail direct fuel injection, increasing numbers of smaller vehicles are diesel-powered with the result that fueling errors are now more common.
FIG. 1 is a schematic view 100 of a motor vehicle 106 having an internal combustion engine 104 and a fuel tank 116 connected to the engine 104 by a fuel line 114. A fuel pump 102 supplies fuel to nozzle 112 through tube 110. Nozzle 112 is inserted through fill tube 108 to enable filling of fuel tank 116. Internal combustion engine 104 may be a gasoline engine, in which case fuel pump 102 should be configured to supply gasoline through tube 110 to fuel tank 116 to ensure proper operation of gasoline engine 104. Alternatively, internal combustion engine 104 may be a diesel engine, in which case fuel pump 102 should be configured to supply diesel fuel through tube 110 to fuel tank 116 to ensure proper operation of diesel engine 104. One possible incorrect fueling operation occurs if internal combustion engine 104 is a diesel engine and fuel pump 102 is configured to supply gasoline through tube 110 to nozzle 112. Another possible incorrect fueling operation occurs if internal combustion engine 104 is a gasoline engine and fuel pump 102 is configured to supply diesel fuel through tube 110 to nozzle 112. In either of these two incorrect fueling operations, internal combustion engine 104 would be supplied by the wrong type of fuel through fuel line 114 leading from fuel tank 116, which in both scenarios would contain the wrong type of fuel (i.e., gasoline for the diesel engine, or diesel fuel for the gasoline engine). As described above, diesel fill nozzles are generally configured to be too large in diameter to allow the filling of gasoline fuel tanks with diesel fuel, as the nozzle will not fit through the restrictor hole (see FIG. 12). Conversely, gasoline fill nozzles are small enough in diameter to easily fit into the fill tubes of diesel-powered vehicles.
FIG. 2 is a schematic isometric view 200 of a diesel nozzle 202 entering (directional arrow 216) a diesel fill tube 204 in the prior art. Fill tube 204 comprises an outer tube 206 and an inner tube 208, where outer tube 206 and inner tube 208 are separated by a restrictor 210 with entrance hole 212 configured to fit closely around the outer diameter of diesel nozzle 202.
FIG. 3 is a schematic isometric view 300 of the diesel nozzle 202 of FIG. 2 fitting closely into entrance hole 212 in restrictor 210. A portion 302 of fill tube 202 is shown protruding through entrance hole 212 and into the inner tube 208. In this configuration, diesel nozzle 202 is positioned to supply diesel fuel to the diesel fuel tank (not shown) attached to inner tube 208. FIG. 3 illustrates a correct fueling configuration in which the proper type of fuel (i.e., diesel fuel) may be introduced to a diesel-powered vehicle.
FIG. 4 is a schematic isometric view 400 of a gasoline nozzle 402 entering (directional arrow 416) the diesel fill tube 204 of FIGS. 2 and 3 in the prior art. Note the smaller outer diameter of the gasoline nozzle 402 compared with diesel nozzle 202 in FIGS. 2 and 3. Typical gasoline nozzles have outer diameters of approximately 13/16 inch (approximately 21 mm), while typical #2 low-sulfur diesel nozzles have outer diameters of approximately 15/16 inch (approximately 24 mm).
FIG. 5 is a schematic isometric view 500 of the gasoline nozzle 402 of FIG. 4 fitting loosely into the diesel fill tube 204 of FIGS. 2 and 3 in the prior art. A portion 502 of fill tube 402 is shown protruding through entrance hole 212 and into the inner tube 208. In this configuration, gasoline nozzle 402 is positioned to supply gasoline to the diesel fuel tank (not shown) attached to inner tube 208. FIG. 5 illustrates an incorrect fueling configuration in which the wrong type of fuel (i.e., gasoline) may be introduced to a diesel-powered vehicle. Note that in the prior art there is no physical bar to the insertion of a gasoline nozzle into the diesel fuel tube, thus the incorrect fueling operation illustrated in FIGS. 4 and 5 is possible, and indeed, commonly occurs accidentally. As discussed above, the consequences of supplying gasoline to a diesel internal combustion engine may include serious damage to internal components of the diesel engine arising from premature explosion of the gasoline within the engine cylinders (due to the higher compression ratios compared with gasoline engines), as well as a lack of natural lubrication for engine components (diesel fuel oil is a lubricant, while gasoline is not). Thus it is an object of the present invention to alert individuals who are attempting to refuel a diesel-powered vehicle using gasoline that an incorrect fueling operation is being attempted, before gasoline has been introduced to the diesel fuel tank of the vehicle, thus avoiding costly repairs even in the case where the diesel engine is not actually operating on gasoline (i.e., the gasoline only contaminates the fuel system leading up to the engine).
In response to the need to reduce fueling errors, a number of mechanical methods have been proposed. An early example is illustrated in U.S. Pat. No. 3,911,977, issued Oct. 14, 1975, describing a filler pipe end structure. More recent examples include U.S. Pat. No. 5,249,612, issued Oct. 5, 1993 for an apparatus and method for controlling fluid dispensing employing complex electronic sensing means. Purely mechanical approaches are described in U.S. Pat. No. 6,302,169, issued Oct. 16, 2001, covering a purely mechanical diesel fuel nozzle restrictor. Another purely mechanical device for preventing entry of gasoline into a diesel-powered vehicle is described in U.S. Pat. No. 6,923,226, issued Aug. 2, 2005, and EP1854653, published Nov. 14, 2007.
These approaches require modifications to the gas dispensing system and/or modifications to the gas tank filler neck. This makes wide spread adoption of these solutions difficult, because gas stations are hesitant to modify pumps before a significant number of automobile filler tanks are modified to work with the new nozzles, and automobile manufacturers are hesitant to modify cars until a significant number of gas stations have modified nozzles.
The problem of putting the wrong fuel in a tank is not limited to a consumer filling a tank in his automobile, but can extend to workers filling fuel trucks with an incorrect fuel, or a fuel truck operator putting an incorrect fuel into an underground tank at a gas station or into an above-ground commercial or agricultural tank. For example, a worker could put gasoline in the diesel tanker truck or diesel in the gasoline tanker truck. The incorrect fuel is put into the ground holding tanks at the gas station or convenience store. As a result, hundreds of vehicles would be affected because the owner/operator of the gas pumps doesn't recognize the wrong fuel has been put in his underground storage tanks until a customer has problems and complains.
Thus, there is a twofold problem: How to stop the driver of the tanker trunk from putting the wrong fuel in the underground tanks; and how to eliminate filling the delivery truck with the wrong fuel. The problem is preferably eliminated by stopping the delivery truck from being filled with the wrong fuel at the distribution level.
It is an object of the present invention to configure the diesel fill tube and gasoline fill nozzle to send a warning signal to the person fueling the vehicle that an incorrect fueling operation is being attempted, before any gasoline has been introduced into the diesel fuel tank and without requiring alteration of the filler nozzle or the filler tank neck.